"I have accepted the resignation of Scott Pruitt as the Administrator of the Environmental Protection Agency," tweeted the president, ending months of speculation about the future of the man he had tasked with dismantling former president Barack Obama's green legacy.

The Trump administration is moving to roll back the centerpiece of President Barack Obama's efforts to slow global warming, seeking to ease restrictions on greenhouse gas emissions from coal-fired power plants.

Obama told an audience of government ministers, business leaders and young environmental activists they were part of a generation with the scientific means and imagination to begin to repair the planet.

The U.S. Department of Energy will release a study of electric grid reliability on Wednesday night, a department official said, an endeavor the renewable industry worries may fault surging solar and wind power for weaknesses on the grid.

The Interior Department has put on hold changes to how the federal government values huge volumes of coal extracted from public lands, primarily in the Western United States, after mining companies challenged the agency in federal court.